Assuming we all have, or had, the same problem, it's a simple fix. In February, I discovered that neither I, nor the auto AC system could control the blower. My dealer comp'd me on the repair, even though I was two weeks out of factory warranty.
Problem was a shorted variable blower control module. Dealer said it was less than a $250 fix (the exact amount didn't appear on my work order). Check the service manual "stickie" here for repair guidelines, then order the replacement part from Courtesy Nissan. I can't imagine that it's a difficult replacement process.